Late Quaternary clay mineralogy of ODP Site 177-1089 and core PS2821-1 in the Southern Cape Basin

The reconstruction of detrital sources and modes of sediment transport gives insight into the operational modes of regional current systems in response to climate variability over the last 590kyr, as inferred from sedimentological and mineralogical parameters of the terrigenous sediment fraction.

Terrigenous sediments mainly originate from African sources with minor contributions from distant southern sources (South America and Antarctica) and are supplied by circumpolar water masses, North Atlantic Deep Water (NADW), and surface currents of the Agulhas Current. Changes in clay mineralogy as tracers of deep and shallow ocean circulation, best displayed by variations in quartz/feldspar ratios and kaolinite/chlorite ratios of clay, reflect both the northward displacement of NADW injection into the Antarctic Circumpolar Current and a weakening of Agulhas Current leakage from the Indian Ocean around South Africa to the South Atlantic during glacial stages, sub-stages, and stadials.